CVE-2023-6871

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-12-19 · updated 2026-06-17

Description

Under certain conditions, Firefox did not display a warning when a user attempted to navigate to a new protocol handler. This vulnerability affects Firefox < 121.

Affected products

Mozilla Firefox: before 121.0 — fixed in 121.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 121.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1828334
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-56/
https://bugzilla.mozilla.org/show_bug.cgi?id=1828334
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-56/

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